The present invention relates to improvements in cartridges containing a disk serving as a recording medium.
FIG. 11 is a perspective view of a conventional cartridge 6. The cartridge 6 comprises a pair of upper and lower half segments 2, 3 butting against each other and contains a disk 60 serving as a recording medium. The upper half segment 3 has an aperture 61 formed in its top wall toward one side thereof for partly exposing the disk 60. The aperture 61 is opened or closed by a shutter 4 slidable on the cartridge 6. The cartridge 6 is inserted into a recording-playback device (not shown) in the same direction as the direction of movement of the shutter 4.
A slit 63 is formed in the side wall of the cartridge 6 over which the shutter 4 is provided. When the cartridge 6 is inserted into the recording-playback device, a tooth 10 fixedly provided in the device advances into the slit 63. The shutter 4 is held in engagement with the cartridge 6 by a lock mechanism (not shown). The tooth 10 advancing into the slit 63 unlocks the lock mechanism and pushes the shutter 4 open. In the following description, the direction of insertion of the cartridge into the device will be referred to as xe2x80x9cfront,xe2x80x9d and the opposite direction as xe2x80x9crear.xe2x80x9d
For recording or playback, the cartridge 6 is supported by prop pins 11 projecting upward from a chassis 1 as seen in FIG. 12. The chassis 1 has a turntable 12 and a pickup 13 mounted thereon. The cartridge 6 has formed in its bottom wall a window opening 62 for passing therethrough a beam from the pickup 13 and a through hole 26 for the turntable 12 to pass through. With the shutter 4 opened, the turntable 12 passing through the hole 26 rotates the disk 60, and the beam from the pickup 13 is projected onto the disk 60 through the window opening 62 for the regeneration of signals. For recording signals, a recording head (not shown) is brought into contact with the disk 60 through the aperture 61.
However, the cartridge described has the following problem.
With the cartridge 6 of FIG. 11, the shutter 4 remains open if released from the lock for one cause or another and opened inadvertently, consequently permitting extraneous matter in the air to readily pass through the aperture 61 and adhere to the disk 60. Accordingly, it appears useful to form an insertion opening 31 in the side wall of the cartridge 6 and insert a torsion spring 5 into the cartridge 6 through the opening 31 to bias the shutter 4 in a closing direction by the spring 5 as indicated in chain lines in FIG. 11. The expedient comprising a torsion spring 5 is already actually used, for example, for floppy disks, such that the shutter 4 is automatically closed if opened inadvertently.
The insertion opening 31 formed in the side wall of the cartridge 6 is nevertheless likely to permit ingress of extraneous matter through the opening 31. The extraneous matter will then cause damage to the disk 60 or interfere with the action of the torsion spring 5.
An object of the present invention is to provide a cartridge which has a torsion spring enclosed therein for biasing the shutter in the closing direction and which is diminished in the likelihood of extraneous matter ingressing into the cartridge through an insertion opening.
A cartridge 6 comprises half segments 2, 3 butting against each other. An insertion opening 31 is formed in a side portion of the assembly of the cartridge half segments 2, 3 for permitting insertion of a torsion spring 5 therethrough from outside.
A protective wall 20 is provided upright at the side portion of the half segments 2, 3 between the insertion opening 31 and a disk 60 to define a space by the wall and the upper half segment 3.
The space is so sized as to permit the torsion spring 5 to pass therethrough while leaving a small clearance, with legs 51 thereof directed laterally.